Magnetic repulsion geneva movement



May 13, 1947. 1 l. MENDELSOHN MAGNETIC REPULSION GENEVA MOVEMENT 26, '1945 2 Sheets-Sheet l Vingt.

Filed Sep.

Inventor' l Lewis I. Mendelsohn, 13H

His Abborhe'g.

May 13, 1947. 1 i. MENDELSOHN MAGNETIC REPULSION GENEVA MOVEMENT Filed Sept. 26, 1945 2 Sheets-Sheet 2 Inventor:

.m www. e n d Yr ngo ma I.. A

mp Pwd,

Patented May 13, 1947 MAGNETIC REPULSION GENEVA MOVEMENT Lewis I. Mendelsohn, Lynn, Mass., assignor to General Electric Company, a corporation of New York Application September 26, 1945, Serial No. 618,773

(Cl. 23S-91) 7 Claims.

My invention relates to a Geneva movement gearing arrangement wherein the advance of the driven member of the movement is produced by repulsion 'of magnetic forces. The invention is particularly useful in meter driven registers where a step advancing operation of one or more cyclometer type counting drums or wheels is desirable with a minimum. of frictional load on the meter, since the invention minimizes the friction of the conventional Geneva drive and requires no springs or weights for its operation.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding of my invention, reference is made in the following description to the accompanying drawing in which Fig. 1 represents a sectional side View of a meter register equipped with my invention; Figs. 2 and 3 are fragmentary plan views of the drive of Fig. l which will be referred to in explaining the repulsion action; Figs. l and show other possible driving arrangements ernbodying th'e invention.

In Fig. 1, I have represented a partial face view of a register mechanism having unit, tens, hundreds, and thousands counting drums l, 2, 3, and ll. The drums are interconnected by driving means such that they all rotate in the same direction, right to left, as viewed in Fig. 1, and so that the tens drum 2 makes ,-16 revolution for each complete revolution of the unit drum l, the hundreds drum 3 makes T16 revolution for each complete revolution of the tens drum 2, etc. Also, all drums except the unit drum are advanced in steps of brevolution each, such that the numeral indications thereon are correctly positioned in the windows 5 as shown, except during the instant of advance from one numeral to the next. The present invention concerns permanent magnet means associated with the unit drum for accomplishing such step advancing operation. It is noted that the shafts G of the drums and the shafts 1 of the transfer gears 8 between the drums are vertical and have step bearings 9 in the lower wall i8 of the casing Il. This in itself reduces friction as compared to horizontal shafts and also allows for the use of large, easily read, upright numerals on the drums.

The unit drum l together with a gear l2 and driving dog [3 are secured to the unit drum shaft E and are driven through gear I2, a gear lli, and shaft It from a meter or other apparatus, not shown. The register may for instance be that of a watthour meter.

Below dog I3 on shaft 6 of the unit drum is a driven disk member I6 having a slot l1 therein into which the turned-down end of dog I3 loosely extends. The slot is wide enough so that lost motion amounting to about T16 of a revolution is permitted in the drive between the dog and disk member lfa. Disk member i6 is mounted on a hub i8 with a permanent magnet I9 of bar shape and extending diametrically across the axis of rotation. Hub i8 is free to rotate on shaft 8 within the limits permitted by the lost motion connection l-IL The disk member I8 has a driving tooth part 28 punched out of its rim and this tooth part is adapted to mesh with and drive the transfer gear 8 to the next or tens drum 2 when part 2i) moves past transfer gear 8. The transfer gear has eight teeth but the lower ends of every other tooth are cut off. llhe lower fourtoothed portion of the transfer gear 8 cooperates with the disk member i6 to lock the transfer gearv from rotation except when tooth part 20 is in driving relation with the upper part of gear 8. At the time of such driving relation the adjacent lower tooth of gear 8 opposite disk member l5 enters the slot 2l formed in disk I6 by the punched-out part 20 and hence gear 8 is allowed to rotate 1A; revolution. At other times attempt to rotate gear 8 is prevented by the lower teeth coming against the full rim of disk member i6. Thus in Fig. 2 the tooth of gear 8 which overlies disk H3 is cut off opposite the disk, while the two adjacent teeth of gear 8 are locked from rotation by the disk It. Disk l5 can, however, rotate clockwise driving gear 8 with along tooth of the latter entering opening 2|. The rst transfer gear 8 meshes with a 20-tooth gear 22 secured to the shaft of the tens drum 2 so that when the toothed part 28 of disk I8 advances gear 8 1A, revolution, drum 2 is advanced 1% revolution. The drives for the following drums 3 and Il are similar in operation to the transfer gear drive described. It now remains to be explained how when tooth part 28 drives gear 8, it does so in a quick advancing action even though drum I roi tates slowly and conforms to the speed it is driven by the meter.

Secured to the floor of the casing and lying diametrically across the axis of rotation of the shaft 6 of the unit drum I just below permanent magnet I9 is a second permanent bar-shaped magnet 23. Magnet 23 is positioned so as to be parallel to magnet I8 when the toothed member 29 of disk I6 is about to contact and drive transfer gear 8 approximately as represented in Fig. 2. The two magnets are polarized so that their adjacent poles are of like polarity at this vtime and hence set up a repelling magnetic force between them. This force resists forward rotation of disk member i6 as magnet i9 approaches the opposing position of magnet 23 until the magnets are exactly parallel at which time the rotative component of the force becomes unstable and as soon as magnet IS passes very slightly beyond alinement with magnet 23, the opposing force drives magnet i9 and disk IG in a clockwise direction in a quick forward step until dog i3 strikes against the upper edge of slot il about as shown in Fig. 3. During this quick repulsion force driving advance of disk IE its tooth 28 drives the transfer gear 8 1/4 revolution, advancing the tens drum 2, lo revolution and bringing the next number on its drum into alinement with window 5. The force for driving drum 2 and subsequent drums is entirely repulsion force. It will also be noted that the magnets I9 and 23 extend both ways although not equally from the axis oi rotation so that there is this repelling force at both ends. This is desirable as it tends to lift the shaft of drum I rather than shove it sideways and, as a consequence, the friction at its step bearing is reduced at the time energy is being stored and is released to advance the following drums 2, 3, etc. rlhe advancing energy is made sufficient to advance all of the following drums 2, 3, etc., simultaneously, which action occurs when the register reading changes from 999 to 1000, for example.

The magnitude of this force can be nicely adjusted by the spacing of the magnets, their size, and length, or their strength.

When disk I6 and its magnet I9 have rotated 180 degrees from the position shown in Fig. 2, there is attraction between the magnets but little side thrust on the shaft. At this time the unit disk member i5 stops rotating until dog I3 has moved from the rear of slot I 'I to its forward end after which the disk is again driven forward with the dog. There is no driving action with the following drums at the time, since the tooth 20 is approximately 180 degrees from the position shown in Fig. 2. It is to be noted that in this 180 degree attraction position just referred to the magnets I9 and 23 while parallel will be displaced endwise relative to each other, whereas in the repulsion position they are substantially superimposed. Hence the repulsion torque will have a higher maximum value than the attraction torque, which is a desirable condition. This is brought about by displacing the centers of the magnets slightly to one side of the axis of rotation. Thus the north poles of the magnets are farther from the axis of rotation than the south poles. When there is repulsion, the magnets are substantially superimposed `and opposing poles are close together, whereas in the attraction position unlike poles are relatively farther apart. The magnetic forces in each case are inversely proportional to the square of the distance between the force producing magnetic poles. The material which I prefer to use for the permanent magnets is an alloy containing 50% copper, 20% nickel, 27.5% iron, and 2.5% cobalt prepared substantially as described in United States Patent No. 2,196,824.

Fig. 4 represents another embodiment of the invention where 24 represents a counting drum or other driven member and is driven in the direction of the arrow through a pin 25 and a driving gear 2G. The pin enters a slot 2l in gear 26 and this connection permits lost motion between the two for the desired angular movement. The pin 25 is a permanent magnet polarized as indicated. At one point in its rotation the north pole of pin magnet 25 comes adjacent to the north pole of a stationary permanent magnet 28. If the rotation of gear 26 be counterclockwise as represented by the arrow, pin 25 will be driven to approximately the position shown by the gear. At this point a strong repulsion force exists between the like poles of the stationary and rotating magnets and as soon as pin 25 iS moved Very slightly past magnet 28, this magnetic force will suddenly drive magnet 25 to the forward end of the slot 2l and advancing drum 24 alike distance. Assuming that the axis of rotation be horizontal, thel stationary permanent magnet 28 may preferably be located adjacent the path of magnet 21 at about the lowest point of its rotation. Thus the sidewise thrust on the rotating parts is in a. lifting direction on the rotating parts. Also assuming that the weight of magnet 25 unbalances the rotatingr assembly, to the extent that this is so, the unbalanced weight assists in driving magnet 25 toward magnet 28 when 25 is moving downward, and 25 is assisted in moving upward by the repulsion forces.

The modification of Fig. 5 is much like Fig. 4 where 24 represents a counting drum and 29 a meter-driven advancing gear. Secured to the hub of drum 24 is a permanent magnet 30 disposed essentially as a spoke of the drum. The magnet 36 and drum 24 are driven counterclockwise by a lost motion driving connection comprising a pair of pins 3l and 32 extending from gear 2S on either side of magnet 30. Adjacent the lovlest point of rotation of magnet 30 is a stationary permanent magnet 33 so polarized that it presents an opposing pole to the outer pole of magnet 3e. The parts are shown in the position where magnet 3) is being driven toward magnet 33 by pin 3l against repulsion force. As soon as magnet 39 is slightly beyond magnet 33, the repulsion force will quickly advance magnet 30 and drum 24 until the magnet 30 strikes pin 32. Here again the magnet 33 is placed to best advantage to reduce the weight of rotating parts on bearingsI and utilizing the weight of magnet 3'* to reduce the load on the driving meter when the repulsion force is being built up, and utilizing such magnetic forces as exist following a repulsion advance operation to assist the meter in lifting weight S8 from its lowest to highest position. While the magnetic force predominates over the unbalanced weight to control the quick advancing operation, there is no reason why we may not employ the best disposition of the magnets to minimize friction and reduce the load variations as explained. While Figs. 4 and 5 will ordinarily have additional counting drums driven at a lower ratio as in Fig. l, such additional drums have not been completely shown, since they may be of conventional construction and a description thereof need not be repeated.

In accordance with the provisions of the patent statutes I have described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new desire to secure by Letters Patent the United States, is:

l. In a mechanical drive, a rotary driving member and a rotary driven member, a lost motion driving connection between said members and means for producing a quick forward advance of the driven member ahead of its driving member at a given point in the path of rotation of the driven member comprising a permanent magnet on the driven member, and a stationary permanent magnet positioned adjacent the path of movement of the driven magnet such that at one point in the path of rotation of the driven magnet a magnetic repulsion force is set up between said magnets suflicient to drive the driven member forward ahead of its driving member.

2. In a mechanical drive, a rotary driving member and a rotary driven member normally driven by the driving member through a lost motion driving connection, means for producing a quick forward advance of the driven member ahead of its driving member at a given point in the path of rotation of the driven member comprising a permanent magnet on the driven member and a stationary magnet adjacent the path of rotation of the driven magnet, said magnets being positioned and polarized such that at said given point in the path of rotation of the driven magnet a magnetic pole thereof is driven past and above a like magnetic pole of the stationary magnet producing a repulsion magnetic force suiiicient to drive the driven member ahead of the driving member and also producing a friction-reducing lifting force on said driven member.

3. In a mechanical drive, a driving member, a driven member, a lost motion driving connection between said members, said members being mounted for rotation on vertical shafts, a permanent magnet on the driven member having its magnetic poles on opposite sides of the axis of rotation of said driven member, a stationary permanent magnet having its magnetic poles on opposite sides of said axis of rotation and located below and sufficiently close to the path of rotation of the driven magnet as to cause the driven member to be driven forward ahead of its driving member by the magnetic repelling force of said magnets as the driven magnet is rotated past the stationary magnet with their like poiles ad jacent each other.

4. In a mechanical drive, a driven member mounted for rotation on a vertical axis, means for driving said member in a given direction, a lost motion driving connection between said driven member and driving means, a bar-shaped permanent magnet driven with said member and having its magnetic axis extending across the axis of rotation of the driven member, a barshaped stationary permanent magnet with its magnetic axis extending across said axis of rotation and located below and suiiiciently close to the driven magnet as to produce alternate forces of attraction and repulsion as the driven magnet is rotated about said axis as the magnets become parallel to each other, said magnets being of approximately the same length and extending further from the axis of rotation at one end than the other and polarized so that during rotation of the driven magnet the like poles of said magnets approach closer to each other than do their unlike poles, and whereby a magnetic repulsion force is produced which is greater than the attraction force and is suilicient to drive the driven member ahead of its driving means to the extent permitted by said lost motion driving connection.

5. In a mechanical drive, driving means, a rotary driven member, a lost motion driving connection through which the driven member is normally driven by said driving means, a permanent magnet driven with said driven member, a stationary permanent magnet having a magnetic pole located adjacent to the path of rotation of a like pole of the driven magnet whereby a force of repulsion is produced between the like poles of said magnets at a given point during each revolution of the driven member, said force being sufcient to drive the driven member ahead of its drive means to the extent permitted by Said lost motion driving connection, and means driven by said driving member only when the latter is thus driven ahead by such repulsion force.

6. In a mechanical drive, a rotary shaft, a cyclometer type of register for registering the integrated rotary movement of said shaft, a drive between said shaft and register including a lost motion driving connection, a rotary magnetic part driven through such connection and a stationary magnetic part out of the path of movement of the rotary magnetic part but closely adjacent said path and past which the rotary magnetic part is driven, said magnetic parts having like magnetic poles such that a magnetic force of repulsion is set up between them when adjacent, causing a quick advance movement of the rotary magnetic part when slightly past the stationary magnetic part which advance is permitted because of the lost motion driving connection, and a counting wheel of said register driven ahead the distance between counting characters thereon with such quick advance movement of the rotary magnetic part and solely by said force of magnetic repulsion.

'7. In a mechanical drive, a driven member mounted for rotation about a horizontal axis, means for driving said member, a lost motion driving connection between said -means and driven member, said driven member having a permanent magnet thereon, the Weight of Said driven member being unbalanced about its axis of rotation, and a stationary permanent magnet positioned beneath and adjacent to the path of rotation of the driven magnet on said member, said magnets being polarized such that in the lowermost rotary position of the driven magnet like magnetic poles of said magnets are closely adjacent and produce a repelling magnetic force sufficient to drive the driven member forward ahead of its driving means to the extent permitted by the lost motion driving connection, the repelling force occasioned by said magnets also tending to compensate for the unbalanced weight of the driven member.A

LEWIS I. MENDELSO'HN.

REFERENCES CITED The `following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,891,101 Le Count Dec. 13, 1932 2,107,373 Edwards Feb. 8, 1938 2,195,311 Hurst Mar. 26, 1940 2,365,510 Barnes Dec. 19, 1944 2,298,573 Little Oct. 13, 1942 FOREIGN PATENTS Number Country Date 420,735 France Dec. 2, 191i) 

